Washington – Use of two pesticides – rotenone and paraquat – is linked to a significant increase in the likelihood of developing Parkinson’s disease, indicates a study released Feb. 11 by the National Institute of Environmental Health Sciences.

The link between the disease and the pesticides was discovered when researchers compared 110 people with Parkinson’s disease to 358 matched control subjects from the Farming and Movement Evaluation Study.

“People who used these pesticides or others with a similar mechanism of action were more likely to develop Parkinson’s disease,” said Freya Kamel, co-author of the paper. Users of these pesticides developed Parkinson’s disease approximately 2.5 times more often than non-users.

The pesticides do not have any residential uses. Rotenone only is used to kill invasive fish species, and paraquat use is restricted to certified applicators, in part because previous studies suggest a possible link between the pesticide and Parkinson’s disease.

The study is scheduled to appear in the journal Environmental Health Perspectives.